initial implementation of code splitting #4408

svn changeset:13561/svn branch:6.4

1 files changed, 31 insertions, 0 deletions

diff --git a/src/com/vaadin/ui/ClientWidget.java b/src/com/vaadin/ui/ClientWidget.java
index 989f70ce55..39aecf1f86 100644
--- a/src/com/vaadin/ui/ClientWidget.java
+++ b/src/com/vaadin/ui/ClientWidget.java
@@ -12,6 +12,7 @@ import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
 import com.vaadin.terminal.gwt.client.Paintable;
+import com.vaadin.terminal.gwt.widgetsetutils.WidgetMapGenerator;
 
 /**
  * Annotation defining the default client side counterpart in GWT terminal for
@@ -35,4 +36,34 @@ public @interface ClientWidget {
      * @return the client side counterpart for the annotated component
      */
     Class<? extends Paintable> value();
+
+    /**
+     * The lazy loading of a widget implementation means the client side
+     * component is not included in the initial JavaScript application loaded
+     * when the application starts. Instead the implementation is loaded to the
+     * client when it is first needed.
+     * <p>
+     * Lazy loaded widgets don't stress the size and startup time of the client
+     * side as much as eagerly loaded widgets. On the other hand there is a
+     * slight latency when lazy loaded widgets are first used as the client side
+     * needs to visit the server to fetch the client side implementation.
+     * <p>
+     * In common situations the default value should be fine. If the widget
+     * implementation commonly used and often on first view it is better set
+     * lazy loading off for it. Also if the component implementation is really
+     * thing, it may by justified to make the widget implementation eagerly
+     * loaded.
+     * <p>
+     * Tunings to widget loading can also be made by overriding
+     * {@link WidgetMapGenerator} in GWT module. Tunings might be helpful if the
+     * end users have slow connections and especially if they have high latency
+     * in their network.
+     * 
+     * @return if true (default), the GWT code generator will make the client
+     *         side implementation lazy loaded. Displaying it first time on the
+     *         screen slightly increases, but widgets implementation does not
+     *         stress the initialization of the client side engine.
+     */
+    boolean lazyLoad() default true;
+
 }